1. Field
This disclosure relates to voice over data network calling, more particularly to voice over data network calling that does not require an out of band communication to connect.
2. Background
The ability to make phone calls across data networks has become more prevalent. The technique is typically referred to as Voice over IP (Internet Protocol), Voice over FR (Frame. Relay), or Voice over ATM (Asynchronous Transfer Mode), as examples. Generally, these technologies will be referred to as Voice over X (VoX).
Typically, when two users want to communicate using VoX, they make arrangements in another medium to connect the VoX call. They have to contact each other ‘out of band,’ meaning that they need some other way to communicate prior to making the VoX call. They may send each other an e-mail, fax or phone call using PSTN (public switched telephone network) to arrange the VoX call.
Once the call is arranged, the phone call can be initiated in a number of ways. In a first example, the users are both already connected to the network before the call is connected. In another, one user is connected to the network and initiates the call through the network. The network then has to convert the VoX call data back to voice and initiate a PSTN dialout from the network to the destination phone. Alternatively, the destination phone has to have a pre-assigned network address, allowing the caller to identify the phone by its address. Another alternative is to have the phone permanently connected to the network, so it can always be contacted across the network.
None of these solutions are optimal for wide spread use of network calling. The arrangements to connect by VoX make the VoX call redundant and eliminate the cost savings available by using bandwidth for which payment has already been made. PBX servers must be available for the network to perform dialing out of the network to make contact with the PSTN. Preassigned network addresses are not usually scaleable, limiting the number of devices that can be on network hubs, as well as being wasteful of unused or little used addresses. Finally, permanently connecting phones to the network is more expensive and again does not capitalize on the advantages of network calling.